Page:Evolution of Life (Henry Cadwalader Chapman, 1873).djvu/95

Rh the running birds are older than the ordinary birds; this harmonizes with the fact that the running birds are of existing birds the most nearly allied to the Dinosauria, the supposed ancestors of birds. The birds called Penelope (Cranes) are generally classed with the scratching birds, but they seem to be more nearly allied to the Rhea, Emeu, and Cassowary, and are joined with them, and called by Haeckel Saurophalli. The tree of descent would be then Dinosaurian reptiles, represented by Compsognathus, etc. Changed into Archeopteryx-like forms, the most ancient of birds, the modified posterity of the Archeopteryx would be represented by the Penelope, Rhea, Emeu, Cassowary, having three toes. The African Ostrich, having only two toes, is probably more modern than the three-toed South American kind, or. Rhea. The Cassowary, through the Dinornis, leads up to the Apteryx, while the Emeu and its posterity seem to have remained unchanged. The Penelopidse are probably the ancestors of the scratching birds, to which are nearly allied the recently extinct Dodo of the Mauritius, and the doves and pigeons. The ducks seem to form the transition between the Saurophalli and the swimming birds, though it must be remembered that the Penguin in its separated metatarsals (bones of the foot) would indicate an ancient bird. The swimming birds gave rise probably to the wading birds. All these birds, excepting the doves, leave the egg in a condition fitted to nourish themselves; whereas the doves, pigeons, etc., and their descendants, leave the egg blind, and are nourished by their parents. The pigeons and doves, descending through the Pteroclidae from the scratching birds, probably divided into two branches, the Clamatores (crows, etc.) and the Climbers (woodpecker, etc.); the Clamatores were gradually improved into our singing birds, and the climbing birds into birds of prey.